Compositions comprising functionalized polyphenylene ether resins

ABSTRACT

The invention relates to a polyphenylene ether resin containing residual aliphatic unsaturation as well as composites, blends, and articles made from the polyphenylene ether resin containing residual aliphatic unsaturation. Also included are reaction products between the polyphenylene ether resin containing residual aliphatic unsaturation and other resins and unsaturated resin formulations, e.g., thermosetting polyesters, acrylics, bismaleiimides, silicones, and allylics, and thermoplastics such as polyolefins, styrenics, rubbers, etc.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. application Ser. No.10/063,152 filed 26 Mar. 2002, which is a division of U.S. applicationSer. No. 09/683,352 filed 18 Dec. 2001, which is a division of U.S.application Ser. No. 09/613,112 filed 10 Jul. 2000.

BACKGROUND OF INVENTION

[0002] Polyphenylene ether resins (hereinafter “PPE”) are commerciallyattractive materials because of their unique combination of physical,chemical, and electrical properties. Furthermore, the combination of PPEwith other resins provides blends that result in additional overallproperties such as chemical resistance, high strength, and high flow.

[0003] One technical obstacle to the development of such blends is thelack of compatibility between PPE and many resins. This lack ofcompatibility manifests itself often through very poor physicalproperties as well as delamination in molded parts. Methods have beendeveloped to improve the PPE compatibility with many resins such as, forexample, with polyesters and polyamides. One of the more effectivemethods involves functionalizing PPE to make functionalized PPEcontaining moieties such as acid, anhydride, epoxy, orthoester, and thelike that are reactive with the other resin in the blend. It is believedthat when the functionalized PPE is allowed to react with the otherresin that relatively small amounts of copolymer between the resins areformed. The copolymer is believed to be in large part responsible forimproved compatibility between the PPE and the other resin. Indicationsof improved compatibility include resistance to delamination, improvedphysical properties such as increased tensile and impact properties anda stabilized morphology between the blend component phases under staticand/or low shear conditions.

[0004] Methods to prepare functionalized PPE have included solutionfunctionalization with an acid halide containing compound, such astrimellitic anhydride acid chloride, to make an endcapped PPE containingat least one reactive moiety such as acid, anhydride, epoxy, orthoester,and the like. This method is rather limited in the variety offunctionalized PPE that can be made. Also, the by-products from thecapping reaction tend to cause emulsion and/or isolation issues in thesolvent precipitation stage of the process.

[0005] Another known method to prepare functionalized PPE related tomelt functionalization of the PPE in an extruder. This method involvedmelting and mixing PPE with a functionalizing agent to result in afunctionalized PPE. The functionalizing agent is typically a compoundcontaining a carbon-carbon double or triple bond and one of theaforementioned reactive moieties and is believed to react through theunsaturated bond to functionalize the PPE. Additional polymers could befed into the same extruder or alternatively, the functionalized PPEcould be isolated and subsequently used to prepare other compositions.Melt functionalization has issues, such as difficulty in feeding PPEinto the extruder due to low bulk density and wide particle sizedistribution. Moreover, PPE are often powders and require specialhandling to avoid potential dust explosion.

[0006] As explained above, the methods known in the art teachfunctionalization of the PPE with reactive groups such as acid,anhydride, epoxy, orthoester, and the like. However, for blending PPEwith resin systems that involve curing or polymerization reactions,including radical reactions, it would be highly desirable to have a PPEthat contained residual aliphatic unsaturation and capped phenolic endgroups at the same time. Incorporation of unsaturated species onto thePPE to result in an olefinic functionalized PPE may allow for chemicalgrafting to occur between the olefinic functionalized PPE and the otherunsaturated species that are being polymerized. Moreover, the hydroxylgroups that exist on PPE may interfere with radical polymerizationreactions of unsaturated monomers and lead to undesirable lowpolymerization rates of the unsaturated monomer species.

[0007] PPE known in the art typically are of fairly high molecularweight for blending in the melt phase with other polymers and generallyhave in excess of 50 repeat monomer units, most often in excess of 80 ormore repeat monomer units. Consequently, functionalization reactions andisolation methods have been developed for high molecular weight PPE.Although many physical properties, such as tensile properties, areenhanced with the high molecular weight of the PPE in the polymericblend, in other new resin blend compositions, such as, for example, thepolymerization of vinyl-substituted aromatic monomers, the highviscosity of the PPE having more than 50 repeat monomer units isundesirable as it presents difficulty with mixing. Additionally, theoverall number of available endgroups available for chemicalmodification becomes fairly limited as the molecular weight increases.

[0008] For blending PPE with resin systems that involve curing orpolymerization reactions, including radical reactions, it would behighly desirable from the standpoints of low viscosity for mixing and ahigh endgroup number for functionalization to have a PPE that containedresidual aliphatic unsaturation and that has less than 50 repeat monomerunits on average, preferably less than about 35 repeat monomer units onaverage. It is therefore apparent that a need continues to exist fornovel and improved methods to prepare functionalized PPE containingresidual aliphatic unsaturation, especially low molecular weight PPE(i.e. PPE having an intrinsic viscosity less than about 0.30 dl/g asmeasured in chloroform at 30 Â° C.).

SUMMARY OF INVENTION

[0009] The needs discussed above have been generally satisfied by thediscovery of a process for preparing functionalized PPE containingaliphatic unsaturation. In one embodiment, the process comprisesoxidative coupling in a reaction solution at least one monovalent phenolspecies using an oxygen containing gas and a complex metal catalyst toproduce a PPE; and functionalizing the PPE, preferably prior to and/orduring at least one isolation step for devolatilization of the reactionsolvent, with an unsaturated compound of the formula (I):

[0010] wherein R¹ is an aliphatic or aromatic residue, for example,—CH₂— but may be multiple —CH₂— groups, e.g., n can vary from 1 to about10 or more, or alternatively, n may equal zero wherein the formula is anacrylic residue, and wherein each of R², R³, and R⁴ are independentlyhydrogen, alkyl, or aryl, and wherein X is a residue of one of thefollowing formulae (II):

[0011] or wherein X is a halogen or a residue of the formula (III):

[0012] wherein R⁷ is an aliphatic or aromatic residue, for example, —C₂—but may be multiple —CH₂— groups, e.g., m can vary from 1 to about 10 ormore, or alternatively, m may equal zero (wherein if n and m both equalzero, the unsaturated compound is an acrylic anhydride), and whereineach R⁸, R⁹, and R¹⁰ are independently hydrogen, alkyl, or aryl. In apreferred embodiment, the unsaturated compound is of the formula (IV):

[0013] wherein each of n, R¹, R², R³, and R⁴ are as previouslydescribed. In an especially preferred embodiment, the unsaturatedcompound is of the formula

[0014] The description that follows provides further details regardingvarious embodiments of the invention.

DETAILED DESCRIPTION

[0015] One embodiment of this invention provides for a process for thepreparation of functionalized PPE containing aliphatic unsaturation,preferably having an intrinsic viscosity between about 0.08 dl/g and0.60 dl/g, more preferably between about 0.10 dl/g and about 0.30 dl/g,by oxidative coupling at least one monovalent phenol species, preferablyat least a portion of which have substitution in at least the two orthopositions and hydrogen or halogen in the para position, using an oxygencontaining gas and a complex metal-amine catalyst, preferably a copper(I)-amine catalyst, as the oxidizing agent and, preferably extracting atleast a portion of the metal catalyst as a metal-organic acid salt withan aqueous containing solution, and functionalizing the PPE with theaddition of at least one unsaturated anhydride of the formula (I) priorto and/or during at least one isolation step for removal of the reactionsolvent. In one embodiment, the functionalization is at least partlydone in a flash process to concentrate the PPE reaction solution. Inanother embodiment, the functionalization is at least partly done priorto a flash process to concentrate the PPE reaction solution. In yetanother embodiment, the functionalization is at least partly done in adevolatilizing extruder. The functionalization reaction is preferablydone in the presence of at least one catalyst, preferably an amine-typecatalyst. These and other embodiments will become apparent in thedescription that follows.

[0016] The PPE employed in the present invention are known polymerscomprising a plurality of structural units of the formula (VI):

[0017] wherein each structural unit may be the same or different, and ineach structural unit, each Q¹ is independently halogen, primary orsecondary lower alkyl (i.e., alkyl containing up to 7 carbon atoms),phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, or halohydrocarbonoxywherein at least two carbon atoms separate the halogen and oxygen atoms;and each Q² is independently hydrogen, halogen, primary or secondarylower alkyl, phenyl, haloalkyl, hydrocarbonoxy or halohydrocarbonoxy asdefined for Q¹. Most often, each Q¹ is alkyl or phenyl, especially C₁₋₄alkyl, and each Q² is hydrogen.

[0018] Both homopolymer and copolymer PPE are included. The preferredhomopolymers are those containing 2,6-dimethyl-1,4-phenylene etherunits. Suitable copolymers include random copolymers containing suchunits in combination with (for example) 2,3,6-trimethyl-1,4-phenyleneether units. Also included are PPE containing moieties prepared bygrafting vinyl monomers or polymers such as polystyrenes and elastomers,as well as coupled PPE in which coupling agents such as low molecularweight polycarbonates, quinones, heterocycles and formals undergoreaction in known manner with the hydroxy groups of two poly(phenyleneether) chains to produce a higher molecular weight polymer, provided asubstantial proportion of free OH groups remains.

[0019] The molecular weight and intrinsic viscosity of the PPE can varywidely, depending at least in part on the intended end-use for the PPE.The intrinsic viscosity (hereinafter “I.V.”) of the PPE is most often inthe range of about 0.08-0.60 dl./g., preferably in the range of about0.10-0.49 dl./g., more preferably in the range of about 0.10-0.30dl./g., as measured in chloroform at 25Â° C. In one especially preferredembodiment, the PPE has an I.V. in the range of about 0.10-0.25 dl./g.One unexpected aspect of the process is the ability to utilize a verywide range of I.V.

[0020] The PPE are typically prepared by the oxidative coupling of atleast one monohydroxyaromatic compound such as 2,6-xylenol,2,3,6-trimethylphenol, or mixtures of the foregoing by methods known inthe art. Catalyst systems are generally employed for such coupling andthey typically contain at least one heavy metal compound such as acopper, manganese, or cobalt compound, usually in combination withvarious other materials.

[0021] It will be apparent to those skilled in the art from theforegoing that the PPE contemplated in the present invention include allthose presently known, irrespective of variations in structural units orancillary chemical features.

[0022] The functionalizing agents used in the present invention tointroduce the aliphatic unsaturation onto the PPE are unsaturatedcompounds of the formula (I):

[0023] wherein R¹ is an aliphatic or aromatic residue, for example,—CH₂— but may be multiple —CH₂— groups, e.g., n can vary from 1 to about10 or more, or alternatively, n may equal zero wherein the formula is anacrylic residue, and wherein each of R², R³, and R⁴ are independentlyhydrogen, alkyl, or aryl, and wherein X is a residue of one of thefollowing formulae

[0024] alternatively, X may be a halogen or may be a residue of theformula (III):

[0025] wherein R⁷ is an aliphatic or aromatic residue, for example,—CH₂— but may be multiple —CH₂— groups, e.g., m can vary from 1 to about10 or more, or alternatively, m may equal zero (wherein if n and m bothequal zero, the unsaturated compound is an acrylic anhydride), andwherein each R⁸, R⁹, and R¹⁰ are independently hydrogen, alkyl, or aryl.In a preferred embodiment, the unsaturated compound is of the formula(IV):

[0026] wherein each of n, R¹, R², R³, and R⁴ are as previouslydescribed. In an especially preferred embodiment, the unsaturatedcompound is of the formula (V):

[0027] However, included within the scope of the present invention are“mixed” or “unsymmetrical” anhydrides of formula (IV).

[0028] Although not wishing to be bound by any theory on the nature ormechanism of the chemical reaction between the PPE and the unsaturatedcompound of formula (I), it is presumed that the functionalization ofthe PPE takes place through the hydroxyl groups on the PPE resulting ina PPE containing aliphatic unsaturation comprising the formula (VII):

[0029] Q², n, R¹, R², R³, and R⁴ is as previously defined and jcomprises a range of values generally on average between about 10 and110 depending in large part on the I.V. of the PPE. In one embodiment, jhas an average value less than 49. In another embodiment, j has anaverage value less than 34. In a preferred embodiment, the PPEcontaining aliphatic unsaturation comprises the formula

[0030] R², R³, and R⁴ is as previously defined. In an especiallypreferred embodiment, n is zero, R² is CH₃ or hydrogen and both of R³and R⁴ are hydrogen. There can also be multiple aliphatic unsaturationintroduced onto the PPE through incorporation of branching agents and/orcoupling agents into the PPE backbone structure such that more than oneend of the PPE contains hydroxyl groups for capping. Such branchingagents and/or coupling agents are known in the art and include compoundssuch as, for example, tetramethylhydroquinone and trishydroxyphenol.

[0031] The functionalization reaction is preferably performed in asolvent, preferably in the polymerization reaction solvent. Suitablesolvents are disclosed in the above-noted Hay patents. Aromatic solventssuch as benzene, toluene, ethylbenzene, xylene, and o-dichlorobenzeneare especially preferred, although tetrachloromethane, trichloromethane,dichloromethane, 1,2-dichloroethane and trichloroethylene may also beused.

[0032] One unexpected advantage of the present process when used to makefunctionalized low I.V. PPE is that a higher solids loading is possibleas compared to processes that make higher (i.e. >0.28 I.V.) PPE. Withoutthe increased solution viscosity build that concomitantly accompanieshigh molecular weight polymer, the final solids concentration can beincreased by at least 20%, with increases of 30% or more possible. Thus,the present process affords a method for increased reactor utilizationand productivity without increasing the size or number of the reactorvessels.

[0033] The temperature to carry out the functionalization stage of theinvention generally ranges from about 20Â° C. to about 100Â° C.,although higher temperatures are also possible. More preferably, thetemperature range is from about 45Â° C. to about 80Â° C. Atsubstantially higher temperatures, side reactions can occur leading toreaction by-products. One unexpected advantage of the present process isthe relatively low temperatures that can be utilized and still achievehigh levels of functionalization at acceptable reaction times.

[0034] After removal of the catalyst, the PPE containing solution isconcentrated to a higher solids level as part of the isolation of thePPE. It was unexpectedly found that PPE can be readily functionalized toa PPE containing aliphatic unsaturation prior to and/or during thissolvent removal process by addition of at least one functionalizingagent of the formula (I). The location of the addition of the at leastone functionalizing agent will depend on several factors such as thestability of the agent, the volatility of the agent to the isolationconditions, the flexibility of the equipment for addition points, andthe like. For functionalizing agents that are volatile in the isolationprocess, addition of the functionalizing agent prior to solvent removalis often preferred so as not to remove the functionalizing agent beforeit has functionalized the PPE. For less volatile functionalizing agents,greater flexibility in the location of the addition is possible. It isalso possible to add functionalizing agent at several points during theprocess.

[0035] The amount of the above mentioned functionalizing agents that isrequired to appropriately functionalize the PPE is that which issufficient to improve the compatibility between the various componentsin the final composition, i.e. between the PPE and the other resins andcomposite formulations, e.g., unsaturated polyesters, acrylics, andthermoplastics such as polyolefins. As previously discussed, indicationsof improved compatibility include resistance to delamination, improvedphysical properties such as increased tensile and impact properties anda stabilized morphology between the blend component phases under staticor low shear conditions. For the most part, it is desirable for allhydroxy end groups on the PPE to be capped by the method of thisinvention. However, the invention includes compositions which contain aproportion of uncapped PPE; that is, PPE containing terminal hydroxygroups.

[0036] An effective amount of the above mentioned unsaturated compounds,based on the amount of the PPE, is generally up to about 3 molarequivalents, and is preferably up to about 2 molar equivalents, mostpreferably up to about 1.2 molar equivalents, all based upon the amountof terminal hydroxyl groups on the PPE as determined by FT-IR, usuallyin carbon disulfide. The actual amount utilized will also depend on, forexample, the reactivity of the unsaturated functionalizing agent withthe PPE hydroxyl groups, the catalyst employed, the reaction conditions,and the degree of capping that is desired in the PPE.

[0037] The capping efficiency and rate are improved by the addition ofat least one catalyst. Although a wide variety of catalysts are useful,a particularly useful group of catalysts include the tertiary amines. Itwas unexpectedly found that 4-dialkylaminopyridines, such as4-dimethylaminopyridine, as well as 4-pyrrolidinopyridine are especiallyuseful for achieving high conversions at short reaction times under mildconditions as compared to other tertiary amines. The amount of catalystcan vary widely, however, the amount is generally an amount effective toimprove the degree of conversion under a given set of reactionconditions as compared to the degree of conversion under the sameconditions without the catalyst. Useful amounts generally range fromabout 0.1% by weight to about 10% by weight, preferably from about 0.5%by weight to about 5% by weight based on the amount of the PPE. An exactamount can be readily determined by statistical analysis under thereaction conditions, including the actual functionalizing agentreactivity, the reaction conditions, the equipment available, and thelike without undue experimentation.

[0038] The functionalized PPE may be isolated in a variety of ways,including precipitation methods and total isolation methods. A totalisolation process is often preferred for isolating the functionalizedPPE when the I.V. is less than about 0.25 dl/g as measured in chloroformat 25Â° C. As part of the total isolation, a portion of the solvent ispreferably removed in order to reduce the solvent load on the totalisolation equipment. Concentration of the PPE containing solution ispreferably accomplished by reducing the pressure in a solvent flashvessel while preferably increasing the temperature of the PPE containingsolution. Pressures of about 35 to 50 bar are desirable with solutiontemperatures increased to at least 200Â° C., preferably of at least230Â° C. A solids level of PPE of at least 55%, preferably of at least65% or higher is desirable.

[0039] The unsaturated functionalizing agent can be effectively added tothe PPE at several locations during the isolation process. For example,functionalizing agent may be added prior to removal of solvent, thefunctionalizing agent may be added during the concentration of thereaction mixture, or both. Likewise, functionalizing agent can be addedwith the concentrated reaction solution into the final devise forsolvent removal. Functionalizing agent may alternatively be addedsimultaneously at several different locations. The selection of theaddition location may be dictated by the actual equipment utilized andby the properties of functionalizing agent with a determination of anoptimum location.

[0040] For total isolation processes, the final isolation of thefunctionalized PPE is preferably carried out in a devolatilizingextruder although other methods involving spray drying, wiped filmevaporators, flake evaporators, and flash vessels with melt pumps,including various combinations involving these methods are also usefuland in some instances preferred. As previously described, totalisolation is preferable from the viewpoint that oligomeric species arenot removed to the same degree as with precipitation. Likewise,isolation yields are extremely high and are near quantitative. In thesetechniques it is highly preferred that the PPE polymerization catalyst(i.e. metal catalyst) removal be completed in the prior process steps asany metal catalyst remaining in solution will necessarily be isolated inthe PPE.

[0041] Devolatilizing extruders and processes are known in the art andtypically involve a twin-screw extruder equipped with multiple ventingsections for solvent removal. The devolatilizing extruders most oftencontain screws with numerous types of elements adapted for suchoperations as simple feeding, devolatilization and liquid sealformation. These elements include forward-flighted screw elementsdesigned for simple transport, and reverse-flighted screw andcylindrical elements to provide intensive mixing and/or create a seal.Particularly useful are counterrotating, non-intermeshing twin screwextruders, in which one screw is usually longer than the other tofacilitate efficient flow through the die of the material beingextruded. Such equipment is available from various manufacturersincluding Welding Engineers, Inc.

[0042] In the practice of one embodiment of the present invention, thepreheated concentrated solution containing the functionalized PPE is fedinto the devolatilizing extruder and maintained at a temperature lessthan about 300Â° C., and preferably less than about 275Â° C., withpressures in the vacuum vent of less than about 1 bar. The exacttemperature will depend in large part on the I.V. of the functionalizedPPE and the corresponding viscosity associated with that I.V. resin. Itis noted that the functionalizing agent may alternatively be added atvarious locations along the length of the extruder with good results.The resultant solvent level is preferably reduced to less than about1200 ppm, preferably less than about 600 ppm, and most preferably lessthan about 400 ppm.

[0043] Another unexpected result obtained through the use of adevolatilizing extruder was the extremely high yield of PPE achieved inthe process. For example, a PPE yield of over 99% was obtained even forPPE having a low I.V. (typically on the order of about 0.08 dl/g toabout 0.25 dl/g) whereas in the precipitation process known in the art,the yield of similar low I.V. PPE was less than 90%. Thus, the presentprocess comprising a devolatilizing extruder affords a method to preparefunctionalized low molecular weight polyphenylene ether resin containingaliphatic unsaturation, typically within the intrinsic viscosity rangeof about 0.08 dl/g to about 0.25 dl/g, in a yield of over 90%,preferably over 95%, more preferably over 98% and most preferably over99%, based upon the amount of monovalent phenol utilized in theoxidative coupling.

[0044] When using a devolatilization extruder for the total isolation ofthe low I.V. functionalized PPE as previous described, it was found thattraditional underwater or water spray cooling of strands of extrudatefollowed by chopping the extrudate into pellets gave unacceptableresults presumably due to the low melt strength and inherent brittlenature of low I.V. PPE. It was found that special pelletizationtechniques can overcome these difficulties. Useful techniques includedie-face pelletization, including underwater pelletization and flaking,declining angle strand pelletization using water spraying, and vibrationdrop pelletization with underwater pelletization especially suitable.

[0045] The collected PPE pellets can be dried using techniques standardin the art including centrifugal dryers, batch or continuous ovendryers, fluid beds, and the like. Determination of an appropriate set ofconditions can be readily determined by one of skill in the art withoutundue experimentation.

[0046] As an alternative to completely isolating the functionalized PPE,one or more resins may be added to the devolatilized functionalized PPEin the same process. The one or more resins may be fed into thedevolatilizing extruder although additional extruders may also be used.Possible variations include melt feeding the one or more resins into thedevolatilizing extruder or melt feeding the functionalized PPE from thedevolatilizing extruder into a second compounding extruder as well ascombinations of these. Accordingly, in one embodiment a compatibilizedblend is afforded by the process without complete isolation of thefunctionalized PPE. The one or more resins can vary widely and can alsoinclude additives common to such compatibilized blends. Such additivesinclude impact modifiers, lubricants, flame retardants, pigments,colorants, fillers, reinforcing agents, carbon fibers and fibrils, andthe like. Preferred resins include polyamides, polyesters, polyarylenesulfides, polycarbonates, polyetherimides, polyarylenes, functionalizedpolyolefins, polysulfones, polyethersulfones, and the like.

[0047] The functionalized PPE containing aliphatic unsaturation isespecially useful in composite systems that involve a curing orpolymerization step of unsaturated species, for example, styrene oracrylic-type monomers. It is believed that the aliphatic unsaturationintroduced onto the PPE affords a reaction path to chemically link thePPE into composite system. Moreover, many of these same compositesystems cure or polymerize, at least in part, through radical reactions.Uncapped PPE contains phenyl hydroxyl moieties that interfere with suchradical reactions. In one embodiment, the functionalized PPE containingaliphatic unsaturation has the free hydroxyl groups “capped” reducingthe interference. By “capped” is meant that at least about 80%,preferably at least about 90%, more preferably at least about 95% ormore of the hydroxyl groups of the PPE have been reacted. It should beclear that the present invention also includes reaction products betweenthe PPE containing aliphatic unsaturation and composite systems thatinvolve a curing and/or polymerization step of unsaturated species. Itshould also be clear that the PPE containing aliphatic unsaturation isuseful with a wide range of thermosetting resins, including but notlimited to those selected from the group consisting of epoxy, phenolic,alkyds, polyester, polyimide, polyurethane, mineral filled silicone,bis-maleimides, cyanate esters, vinyl, and benzocyclobutene resins andcan react in a variety of pathways with such resins.

[0048] All patents cited by reference are incorporated herein byreference.

[0049] In order that those skilled in the art will be better able topractice the invention, the following examples are given by way ofillustration and not by way of limitation.

EXAMPLES Polymerization Reaction

[0050] A typical laboratory reaction recipe and reaction conditions areprovided.

[0051] The catalyst solution can be prepared by stirring 0.41 g ofcuprous bromide and 10.9 g of di-n-butyl amine in 100 ml of toluene. Thecatalyst is transferred to a one liter stirred glass reactor equippedwith an internal cooling coil and inlet tubes for oxygen and monomer. Arapid stream of oxygen is introduced near the bottom of the reactor anda solution of 70 g of 2,6-xylenol in 100 ml of toluene is added througha metering pump, over a period of fifteen minutes, to the rapidlystirred solution. The temperature is maintained initially at about 40Â°C. to about 45Â° C./48Â° C. towards the end of the run by circulatingwater from a constant temperature bath through the cooling coil.Molecular weight build is continuously monitored with a typical reactiontime to target I.V. of about 100-107 minutes.

[0052] In the glass reactor vessel, the copper catalyst was complexed bythe addition of a complexant like nitrilotriacetic acid (NTA) or othercopper complexing agent in order to solubilize it in the aqueous liquidphase. The equilibration time was approximately 70 minutes and thetemperature was approximately 55Â° C. The catalyst was removed withcentrifugation.

[0053] Although the conditions are for a laboratory scale reaction theyin general scaleable to commercial processes carried out in commercialequipment without undue burden by one of skill in the art.

General Procedure for Preparing PPE Containing Residual AliphaticUnsaturation

[0054] In a dry 250 ml 3-neck round bottom flask was added a 40 weightpercent solution of PPE in toluene amount and a “magnet” for stirring.The flask was placed in a oil bath, the temperature was set to thereaction temperature. A slow nitrogen purge was applied and maintainedduring the reaction. The catalyst 4-dimethylaminopyridine (DMAP) or4-dimethylbutylamine (DMBA) was added. After 15 minutes, when thecatalyst had dissolved, the reaction was started by adding the amount ofmethacrylic anhydride (MAA). After about 30 minutes, the toluene wasremoved with vacuum stepwise decreasing from atmospheric pressure toabout 40 mm Hg. The sample was dried in a vacuum oven for about 10 hoursat about 120Â° C./10 mm Hg, ground to powder form and dried for another3 hours at 120Â° C./10 mm Hg. The capping conversion was determined onthe totally isolated methacrylic-PPE (by-product as MAA, methacrylicacid and DMAP were not removed). The [OH] content is measured by FT-IR(carbon disulfide). The capping conversion is calculated by the formula:Conversion %=(A-B)/A×100%, A=[OH]PPE ref., B=[OH]Methacrylic-PPE sample.TABLE 1 OH for rx. OH after rx. Conv. MAA Temp. (μmol/g) (μmol/g) (%)(wt % vs PPE) Catalyst (° C.) 344 23 93 5.0 DMAP 80 344 74 78 10.0 DMAP80 344 75 78 5.0 DMAP 260 361 208 42 5.0 DMBA 80 361 124 66 10.0 DMBA 80361 122 66 15.0 DMBA 80 400 204 49 5.0 DMBA 260

[0055] As can be seen by these data, very high conversion to the cappedPPE containing aliphatic unsaturation can be readily achieved. Moreover,it was unexpectedly found that DMAP gave appreciably higher conversionsthat DMBA.

Designed Experimental

[0056] A series of designed experiments were conducted to furtherexemplify embodiments of the invention using the same general procedure.The results are shown in Table 2. TABLE 2 [MAA] in wt % [DMAP] in wt %Conversion (%) 5.5 3 79 6 2 82 6 4 84 7 3 93 8 2 98 8 4 99 8.5 3 100

[0057] As can be seen by the data in Table 2, high conversion can bereadily obtained under a wide variety of conditions illustrating thebroad utility of the present invention.

Total Isolation

[0058] Functionalized PPE containing residual aliphatic unsaturation wasalso prepared and totally isolated.

[0059] Step 1: MAA capping of PPO857 in Toluene. Conditions: 40 wt % PPEin Toluene, 6.5 wt % MAA and 3 wt % DMAP; 90Â° C., 300 rpm stirring, 2hours, Nitrogen; recipe 180.1 g Toluene, 112.7 g PPE, 8.1 g MAA, 3.4 gDMAP. After the reaction, a ca. 20 g sample was poured out on aluminumdisk. The toluene was allowed to evaporate at room temperature. Thematerial was ground and dried for about 8 hours at about 120Â° C./10 mmHg. The material transferred to a “Parr-bomb”, see step 2.

[0060] Step 2: Methacrylic-PPE solution in toluene treatment at hightemperatures and pressures. A 300 ml vessel for high temperature andhigh pressure, so-called Parr-bomb, was filled with solution of step 1.At 70Â° C., flush with nitrogen for about 5 minutes than the vessel wasclosed. After 10 minutes at about 245Â° C., the pressure readout wasabout 45 bar. The temperature was maintained at about 245Â° C. for about30 minutes, then cooled to about 80Â° C. over about 30 minutes. Thesolution was poured out on aluminum disks. The toluene was allowed toevaporate at room temperature. The material was ground and dried forabout 8 hours at about 120Â° C./10 mm Hg, and used for step 3.

[0061] Step 3: Extrusion of Methacrylic-PPE in Prism twin (16 mm screws)extruder. An 80 g sample of totally isolated methacrylic-PPE was used;all by-product were present. Conditions: barrel temperatures from nozzleto throat were 257-283-276-250Â° C.; 250 rpm, 25% Torque (5 Nm). Theextrudate was dried for about 8 hours at about 120Â° C./10 mm Hg,afterwards ground. TABLE 3 Results MAA/PPE reaction for direct isolationdirect % Conversion % double bonds isolation by FT-IR* by NMR** Reactionin 92 83 toluene Treatment high 92 Not determined temperature & pressureExtrusion 90 Not determined

[0062] The data in Table 3 demonstrate that the residual unsaturationcan, unexpectedly, substantially survive the direct isolation thermalconditions. FT-IR analysis done before and after extrusion had criticalpeak ratios that were essentially constant, indicating very littlechange in the amount of double bonds or capping.

Capping of PPE Pellets From Direct Isolation

[0063] A series of capping reactions were conducted using PPE that hadbeen isolated by total isolation using devolatilization of the PPEpolymerization solvent.

[0064] In a typical experiment, to 1000 ml 4-neck round bottom jacketedglass reactor (L/D=1.5) equipped with a 45Â° pitch four-blade agitatoroperating at 1000 rpm was added toluene (311 g) at 40Â° C. followed byPPE pellet (0.12 I.V., 133 g) and the system was purged with nitrogengas. The reaction solution temperature was increased to 60Â° C. and4-N,N′-dimethylaminopyridine (DMAP, 6.7 g, 5% wt based on PPE) wasadded. The resulting solution was heated to 85Â° C., and thenmethacrylic anhydride (MAA, 16g, 12% wt based on PPE) was added. Thesolution was maintained at about 85Â° C. for about 30 to 400 minutesuntil the end capping reaction. At the end of reaction, the reactionsolution was cooled, discharged from reactor, precipitated with 2 timesvolume of methanol, vacuum filtered with 100 mesh filtration cloth andvacuum dried for about 8 hours at 100Â° C. During reaction, every 30minutes, about 1 ml reaction solution sample was taken and immediatelydissolved into 25 ml carbon disulfide for testing of residual OHcontent. The [OH] content is measured by FT-IR (carbon disulfide). Thecapping conversion is calculated by the formula: Conversion%=(A-B)/A×100%, A=[OH]PPE ref., B=[OH]Methacrylic-PPE sample. Theresults of capping PPE pellets in solvent are listed in Table 4. TABLE 4Pre-Pilot capping reaction results t

ch MAA % DMAP % % CAPPED

mp = 85° C. 8 2.75 82.6 8 0.5 81.0 12 5 99.4 8 5 89.7 12 0.5 98.5 8 2.7582.6 10 2.75 98.9 12 5 100.0 12 2.75 99.4

mp = 45° C. 12 2.75 99.4

[0065] The above examples demonstrate the high levels of capping thatcan be achieved using PPE that has been directly isolated by removal ofthe PPE polymerization solvent. It was unexpected that such a highdegree of capping would be achieved without having to pre-wash the PPEsolution to remove impurities from the polymerization reaction.

Large Scale Capping PPE Pellet in Solution

[0066] To illustrate the commercial feasibility of one embodiment of theinvention, to a 300 gal 316 stainless steel reactor (L/D=1.1) equippedwith two layer three blade propeller variable speed agitator (43 to 430rpm) and a jacket and external circulation loop through a heat exchangerto control reaction temperature was added 250 lb. of low I.V. PPE (0.12I.V.) pellets obtained from a total isolation of the PPE reactionsolution using devolatilization equipment with 564 lbs of toluene atroom temperature. To the reaction solution was added 6.9 lbs. (2.75% wtbased on PPE) of 4-N,N′-dimethylaminopyridine (DMAP) and 25 lbs (10% wtbased on PPE) of methacrylic anhydride (MAA). The reaction temperaturewas controlled to about 85Â° C. Essentially 100% OH conversion wasachieved after about 150 minutes as detected by FT-IR analysis.

PPE Pellet Capping in Styrene

[0067] To a three-necked round bottom flask equipped with an overheadmechanical stirrer, a condenser, and a thermocouple was added styrene(200 mL), followed by PPE (0.12 I.V., 181.8 g) and4-N,N′-dimethylaminopyridine (DMAP,1.22 g). The resultant solution washeated to about 85Â° C., and methacrylic anhydride (MAA, 21.8 g) wasadded. The solution was maintained at about 85Â° C. for about 8 hours tocomplete the reaction. The capping efficiency was found to be 98.5%.Table 5 is a summary of results. Results of Clapping Low IV PPE inStyrene Monomer Reaction Reaction Capping Styrene DMAP MAA temp timeefficiency (mL) (g) (g) (° C.) (hrs) (%) 200 5 21.8 85 2 100.0 200 2.521.8 85 4 99.7 200 1.22 21.8 85 8 98.5 200 0.61 21.8 85 17 98.2

[0068] These results illustrate that very high PPE capping conversionscan be achieved in the presence of a polymerizable monomer such as avinyl aromatic material such as styrene monomer.

[0069] One unexpected advantage of capping PPE that has not beenisolated is a reduction in color when used in many applications. Forexample, a 10 weight percent styrene solution of MAA capped 0.12 IV PPEmade from direct capping reaction body feed had a Î

of 56 as compared to a 10 weight percent styrene solution of MAA capped0.12 IV PPE made from capping re-dissolved 0.12 IV PPE pellet in toluenehad a Î

of 66. This reduction in color is unexpected in view of the prior art inwhich one would expect the color to be very similar.

[0070] These and other embodiments should be apparent from thedisclosure contained herein.

1. A composition, comprising: a polyphenylene ether resin of the formula

wherein R¹ is an aliphatic or aromatic residue; n is 0 to about 10; R²is hydrogen methyl; R³ and R⁴ are hydrogen; j has an average value lessthan 49; each Q¹ i methyl; and each Q² is independently hydrogen ormethyl.
 2. The composition of claim 1, wherein R² is hydrogen.
 3. Thecomposition of claim 1, wherein R² is methyl.
 4. The composition ofclaim 1, wherein each Q² is hydrogen.
 5. The composition of claim 1,wherein j has an average value less than
 34. 6. The composition of claim1, wherein the polyphenylene ether resin comprises2,6-dimethyl-1,4-phenylene ether units and 2,3,6-trimethyl-1,4-phenyleneether units.
 7. The composition of claim 1, wherein the polyphenyleneether resin has an intrinsic viscosity of about 0.08 to about 0.25 dl/gas measured in chloroform at 25Â° C.
 8. The composition of claim 1,wherein the polyphenylene ether resin has an intrinsic viscosity ofabout 0.08 to about 0.16 dl/g as measured in chloroform at 25Â° C. 9.The composition of claim 1, further comprising styrene.
 10. Acomposition, comprising: a polyphenylene ether resin of the formula

wherein R¹ is an aliphatic or aromatic residue; n is 0; R² is hydrogenor methyl; and R⁴ are hydrogen; j has an average value less than 49;each Q¹ is methyl; a each Q² is hydrogen.
 11. The composition of claim10, further comprising styrene.
 12. A composition, comprising: apolyphenylene ether resin of the formula

wherein R¹ is an aliphatic or aromatic residue; n is 0; R² is methyl; R³and R⁴ a hydrogen; j has an average value less than 49; each Q¹ ismethyl; each Q² is hydrogen; and wherein the polyphenylene ether resinhas an intrinsic viscosity o about 0.08 to about 0.16 dl/g as measuredin chloroform at 25Â° C.
 13. The composition of claim 12, furthercomprising styrene.